Johnson valiant power usage.

[w1cjf]

This sounds a little off the rocker but thats what i am. I need to know about how many watts a valiant draws at idle. Im building a AM mobile and want to run the valiant in it. Not driving just to a parked location with a full lengh dipole in the woods.  Ive found inverters 5000 watts and 8k being the biggest.  They run full size fridges so im sure it could run a valiant but im unsure. I live in a apartment so no 75am from the home. I plan on putting a 250amp alt in also.

[AB3FL]

According to page 2 of the manual, It says 560 watts key down and 560 watts average on AM.


Tom - AB3FL

[WBear2GCR]

best plan for xtal control or DDS, the VFO is not mechanically too stable... but who knows, maybe it will be ok...

Why not an ART-13?

                  _-_-bear

PS. you might want to consider the expedient of putting a 1kw or so iso transformer in front of that power inverter, as the instantaneous key down current is going to have a big arse peak in there... the iso tranny will provide some "ride through" and smooth out the peak. But maybe these newer generation inverters can handle the juice... definitely put some RF filtering in the AC line though...

[K7EK]

I would also suggest being very careful as to what inverter you buy. Get one that does not put out square or sawtooth waves, otherwise your receiver will be overwhelmed with noise. You would quickly become very disillusioned with the idea if you were not able to hear well.  There's only a few manufacturers that make inverters that put out a pure or near pure sine wave, at a somewhat increased cost.....

Good luck. It sounds like a pretty neat project. I hope we hear you on the air in the near future.

Best regards,

Gary, K7EK

[KA2DZT]

Why not just use a small AC generator if you're going to be operating fixed moble in the woods?  Probably a small 1KW unit would work.  At least the generator will put out a sine wave voltage and shouldn't create any receiver noise.   I've used generators on FD for over 50 years and never had any noise problems.

Fred

[WD5JKO]

wow, all great suggestions. I got a variation that might work. Run the filaments on 12V directly by series parallel, or go to all 12v tubes. Then take a cheap "Quasi-Square" wave inverter and key it with your push to talk circuit. This way the receiver won't hear the hash, and the filaments being powered directly will save some power since each power conversion takes 5-20% of the power drawn and converts it to heat in the inverter.

;;;

OR take a Retro-75 (after de-yellowing the audio), and a 4 pill linear amplifier that makes 150 watts AM right from the car battery.. :-)

my 2.5 cents,
Jim
WD5JKO

[W2VW]

Power conditioners are all over ebay for scrap prices. One of those may smooth out any harmonics from the inverter.

[WA1GFZ]

An isolation transformer will do nothing for you but increase losses. The Valiant has transformers on the input.

[WA2IXP]

Fixed mobile sounds like a good way to get on am with vintage equipment and a full sized ant if your not able to do so from home. I know a guy who has a small trailer set up just for that reason. There are plenty of good inverters now, large batteries, alternators, etc available. One thing to consider is that your car will be idling so most alts no matter what thier rating will not put out alot of current. On transmit you'll need abut 50 amps which might be possible.   I have a small honda inverter generator that works well. Its very quiet, easily carried with one hand. Automatically adjusts engine speed to load so only runs just fast enough for demand. Not cheap but neither is good inverter and alt. A contractor I do work for threw it in the junk pile after he tried to fix the pull cord and couldn't get it apart. Not a simple repair but patients yeilded a good unit. good luk with your project, jay-

[WQ9E]

In addition to possible receiver hash keep in mind that those Valiant transformers are over 50 years old and may not like the spikes and other waveform distortion from the inverter.  I second the suggestion of using a small clean generator for power.

[KA2DZT]

In addition to possible receiver hash keep in mind that those Valiant transformers are over 50 years old and may not like the spikes and other waveform distortion from the inverter.  I second the suggestion of using a small clean generator for power.

That's what I said.

[KE7KPB]

volts x amps = watts.

[w1cjf]

Thanks for the feedback guys!! The valiant is in great shape 100% gone threw by chuck the johnson master and its in great working order. Im going to goto harbor frieght and check out what they have for generators.  I guess i would be considered a "am portable" hahah. The antenna site is 600ft asl so i should have a good straping signal.  I am thinking of using some sort of soild state receiver also. As far as the inverters the price for one i could just easly get or build my own generator.

[KD0HUX]

  The Valiant gives a whole new meaning 2 mobile

[WBear2GCR]

In addition to possible receiver hash keep in mind that those Valiant transformers are over 50 years old and may not like the spikes and other waveform distortion from the inverter.  I second the suggestion of using a small clean generator for power.

That's what I said.

That's why I suggested the expedient of an iso transformer - it won't pass HF stuff and will try to smooth out square-ish stuff... I run a "400 watt" Harbor Freight inverter in several cars (I move it) off the cig lighter and it does not interfere with the AM radio that i have seen thus far. Dunno about 75m though.  Keep in mind you'd need some strapping cable for that inverter to be able to pull real power. The cig lighter connection is good for about 100watts max, no more (@120vac secondary), then the thing sags. Also gotta have the motor on to get that... (I run a laptop on it). So strapescent cable is in order...